Ex-pat Aucklander Ed Kjaer says the long-term economic gains for New Zealand from electric vehicles are beyond those that can be expected for many other countries.

Kjaer is an expert on electric vehicles (EVs), and he makes his living working for one of the largest American utility companies, Southern California Edison (SCE).

California is the electric vehicle capital of the US so Kjaer has seen first-hand their potential to transform motoring and wean economies off dependency on imported oil.

Having left Auckland at the age of 25, Kjaer is returning briefly to speak at Electric Vehicle Symposia in Auckland and Wellington next Thursday and Friday.

He says New Zealand suits EVs particularly well because as with the US, it has excess electricity capacity at night when most people are asleep and when electric vehicles are generally charged.

Urbanites in our main centres tend to have garages where EVs can be charged, whereas half of city-dwellers in the US don't. New Zealand's electricity supply is particularly clean, which offers the possibility of cleaner air and a big dent in the country's carbon emissions.

Also, the New Zealand economy is hostage to volatile oil prices as it has to import nearly all its oil compared to the US which is a big oil producer and is ramping up extraction rapidly.

"The New Zealand economy is a slave to the volatility of gasoline," Kjaer said.

In addition, New Zealand taxes petrol more heavily than the US, making it more worthwhile for households to reduce petrol consumption.

Already, said Kjaer, the lifetime costs of EV motoring beat that of petrol-powered.

Kjaer runs only EVs in his household, charging them at night in the garage, and says he gets the equivalent of 100 kilometres of driving from 1.3 litres of petrol.

His lifetime costs will be significantly less than those of petrol-car owners.

Despite the persuasive cost figures, the EV revolution is still going slowly and part of the problem is that the costs are front-loaded and EVS remain more expensive to buy than petrol cars.

Ask a Prius-driving Auckland taxi driver why they have plumped for a hybrid and the answer is either the green colour they can paint their car to woo customers, or that over the lifetime of the vehicle, they are more cost efficient. But that's not how most people tend to think about EVs, if they consider them at all.

For many the initial cost is daunting and other factors holding back uptake include pre-conceived notions about how EVs drive.

But Kjaer says technology is improving at an impressive rate and all major car makers now have EVs in their ranges.

'It is a marathon not a sprint. It is going to take two to three generations."

The US figures bear that out.

There are about 270 million cars on the road in the US and 14 million new vehicles a year.

"Naught point naught, naught, naught whatever of that are electric vehicles.," Kjaer says.

There's huge potential for utilities like SCE to insert themselves into the vehicle-fuelling business, but the picking are as yet slim, he says.

SCE delivers electricity to around 14 million Americans, its corporate profile boasts, but the number of plug-in vehicle customers is just 8000.

Though the uptake of EVs will be a bottom-up affairs with motorists making the choice for themselves, government has a role to play, and there are a range of possible monetary and non-monetary support mechanisms, Kjaer said.

Non-monetary ways include allowing EVs to use restricted road lanes, or give them preferential parking in the same way disabled people are.

Monetary incentives, and New Zealand does have some modest subsidies, could include things that help reduce the initial purchase price for an EV to get people on the road.